A STEP in the Right Direction

Ask Kulsoom Rahim to talk about her field of research, and it's clear that she loves physics. Even before getting into the specifics of what fascinates her, she appreciates the general scientific worldview studying physics provides: "Knowing things from a scientific perspective, your curiosity is entertained when you know the reasons behind why the world is the way it is," she says, mentioning everything from why a table feels solid to questions of her own field, condensed matter physics. "You know how certain things work, not everything, but certain things."

Rahim is hoping to expand the number of things she knows. She is a Pakistani PhD student at Quaid-i-Azam University in Islamabad, Pakistan. Thanks to a postgraduate fellowship from the Opec Fund for International Development (OFID) which supports visits to ICTP, Rahim is at the Centre for six months to participate in STEP: the Sandwich Training Educational Programme. STEP supports PhD students accepted to universities in developing countries who want to come to ICTP, and other Trieste institutions, to enhance their research and training opportunities. "I came here to get expertise," says Rahim. "My advisor at home and I both started at the same work at the same time," so the knowledge and advice provided by Rahim's advisor at ICTP, Mikhail Kiselev, has been instrumental in advancing Rahim's studies. "I am hoping to add to this field and introduce it at home," she says.

Her field is a branch of condensed matter physics that studies resistivity, or how well a particular material conducts electricity. Rahim explains by starting with electrical wires in a house: they are mostly copper, because it conducts electricity well. But in copper, and other materials, their resistance to conduction, or resistivity, falls drastically as the temperature decreases, reaching a constant value at low temperatures. Rahim is studying a strange exception to this rule: when a material isn't pure, but instead contains even a few atoms of a magnetic element, resistivity plateaus out and remains steady when the temperature gets very cold. Rahim investigates how this odd behavior, known as the Kondo effect, is produced.

Rahim studies the Kondo effect in artificial atoms, called quantum dots. These work as model systems, with unpaired electrons in these artificial atoms closely mimicking the influence of magnetic impurities in metals. Rahim and her colleagues are interested in how the Kondo effect in quantum dots is influenced by electrons' spin-orbit interaction, as a window into how many other phenomena work. This interaction is similar to magnetic fields colliding, with the magnetic moment of a furiously spinning electron affecting the magnetic field of it's orbital motion.

While a laboratory full of quantum dot devices sounds entertaining, Rahim works on the theory side of things, which means writing and solving equations, "and more equations, and more equations, and more equations," she laughs. Rahim's employer university, the University of Engineering and Technology (UET), Taxila, has granted her three years of study leave from her position as a lecturer. For these three years STEP will be funding her periodic trips to ICTP; her hard work on her doctorate degree has a strict deadline. But this is also a good thing: the physics department at her PhD home institution, Rahim explains, "is very vibrant, but unfortunately we only have one professor who is doing condensed matter physics, and many, many students who want to study with him, so timely graduation is important to open places for new students."

When she is not on study leave as part of the STEP program, Rahim teaches physics at her university to undergraduate engineers in classes of 250. "It's a lot of work, but the point is when you're teaching at the undergraduate level, there is a lot of potential for you to influence them," she says. "They're 17, 18 years old, and they have a very raw mind. We need a very big change of mindset in Pakistan," Rahim explains, describing a variety of fronts where she would like to see change.

One of those is multi-level investment in Pakistan's scientific research community. She describes a widespread shortage of research opportunities for interested students in Pakistan, and notes that the time investment and general commitment to research by scientists in Italy is greater than at home.  "In Europe, not only is professional commitment better but professional excellence is better. Our scientists' expertise lags behind Europe and other places, so I want to learn at ICTP and then go and do my part in making my country better. I'm kind of patriotic," she smiles.

If expanding the expertise in her department is her short term goal, Rahim has many corresponding long-term ones. While she hopes to do a post-doctoral fellowship abroad, she always intends to build her career in Pakistan. "I want to pursue a very active career, I don't want it to be a second or third priority in my life." She hopes to be a full professor some day, with her own doctoral students, and to continue her work on open questions in condensed matter physics. While the Kondo effect fascinates her right now, "Within a decade--five to six years--you should start to do something else," she says. "Otherwise you're stagnant, otherwise you run out of ideas, if you don't keep exploring other areas." Her hard work and drive to explore promise that there will be no stagnation in Rahim's future.

--Kelsey Calhoun